Prevent success handler from being erroneously called
Prevent success handler from being erroneously called

Since we're not automatically throwing anymore, we need to take care of
not calling the success handler in case of an error ourselves.

jayfunk/IDBWrapper,jensarps/IDBWrapper,kilbot/IDBWrapper,safetychanger/IDBWrapper,safetychanger/IDBWrapper,jensarps/IDBWrapper,mizchi/idb-wrapper-promisify,jayfunk/IDBWrapper,rubenstolk/IDBWrapper,mizchi/idb-wrapper-promisify,GerHobbelt/IDBWrapper,kilbot/IDBWrapper,rubenstolk/IDBWrapper